Darken specific apps by overlay

[Anish Athalye]

(I got this suggestion via email -- I'm writing down a summary here for reference)

It would be interesting if we could darken specific apps or even windows using a semi-transparent dark overlay. The result might be less contrast between dark and light windows. It also won't suffer from the delays of changing monitor brightness.

There is a disadvantage: Lumen might save some power by allowing you to use a lower brightness when using apps with a light background, while using apps by overlay might make you keep your LCD brightness higher.

Darkening via overlay seems like something technically feasible in macOS. Some related things:

• https://hazeover.com/ -- app that dims background
• http://www.hammerspoon.org/docs/hs.drawing.html -- drawing on screen
• https://gist.github.com/koekeishiya/dc48db74f4fdbfbf5648 -- making a drawing follow windows
• http://www.hammerspoon.org/Spoons/Shade.html - semi-transparent overlay to reduce brightness